1. Field of the Invention
The present invention relates to an identifying apparatus and method, an identifying system and method, a position detecting apparatus and method, a robot apparatus, and a color extracting apparatus, and more particularly, is suitably applied to an autonomous mobile robot.
2. Description of the Related Art
In recent years, the studies of autonomous mobile robots have been advanced as one of mobile robots. The autonomous mobile robot is capable of sequentially fetching information on surrounding environments to determine its actions by itself based on the fetched information.
The following three methods can be thought as methods for a mobile robot as mentioned above to identify other mobile robots (for example, a first machine, a second machine, . . . , and so on). A first method causes respective robots to generate a special signal for identification in the form of radio waves, infrared rays, sonic waves, or the like. A second method paints respective robots in different colors from each other such that the robots are identified based on the colors. A third method adds symbols, bar codes, or the like for identification on surfaces of the respective robots.
The first method, however, requires a special apparatus for transmitting and receiving signals. Besides, regulations stipulated by rules on radio waves and influences to other apparatuses located nearby may not permit desired signals to be transmitted.
The second method may not cause any problem if only a small number of robots are identified because a number of readily identifiable colors may be provided for the number of robots. However, for identifying a large number of robots, the second method must identify subtle differences in color so that the second method requires complicated image processing and is more susceptible to illumination conditions and so on.
In addition, the third method may not observe the signals or the like due to directions and postures of the robot.
On the other hand, the following three methods can be thought as methods of enabling a mobile robot to detect its position within a movable region. A first method adds indicators, such as a color pattern or a signal, on a floor surface of the movable region such that a robot visually reads these indicators. A second method installs transmitters for transmitting radio waves, infrared rays, sonic waves, or the like, on the floor surface and corners of the movable region to permit a robot to detect its position based on the signals from the transmitters. A third method previously gives a robot its initial position by any suitable means such that the robot obtains a moving distance and a moving direction from a driving condition of a moving means of the robot (for example, a rotational number of wheels) and integrates the obtained data in order to detect its current position.
The first method can be realized by a first proposal where a camera disposed on a robot occasionally shoots the floor surface or by a second proposal where a separate camera is provided for monitoring the floor surface.
However, if the first method is to be realized by the first proposal, the robot cannot sufficiently look out its surroundings during directing downward to detect its position. This may cause the robot to collide with another moving object such as another robot. On the other hand, if the first method is to be realized by the second proposal, the provision of a separate camera for monitoring the floor surface causes an increased manufacturing costs an increased weight of the robot, and a more complicated configuration of the robot.
In the second method, if a transmitter is installed on the floor surface within the movable region of a robot, the transmitter itself would be an obstacle to activities of the robot.
Further, in the third method, a limited measuring accuracy in the moving distance and the moving direction of a robot may result in a larger error in a measurement of a current position of the robot. Particularly, if a robot moves over a long distance while frequently changing directions, accumulated errors will become larger and larger, thus it is difficult to correctly detect a current position.